Darshan Dental College, Loyra, Udaipur

Introduction Definition of nutrition according to “Council of food and nutrition of the American Medical Association” as“The science of food, the nutrients and other substances therein ,their action ,interaction and balance in relation to health and diseases and the processes by which the organism ingest, digest, absorbs, transports, utilizes and excretes food substances Nutrients There are six major classes of nutrients: carbohydrates, dietary fiber, fats, minerals, protein, vitamins, and water. These nutrient classes can be categorized as either macronutrients (needed in relatively large amounts) or micronutrients (needed in smaller quantities). The macronutrients include carbohydrates, fats, protein, and water. The micronutrients are minerals and vitamins. The macronutrients (excluding water) provide structural material (amino acids from which proteins are built, and lipids from which cell membranes and some signaling molecules are built), and energy. Some of the structural material can be used to generate energy internally, and in either case it is measured in joules or kilocalories (often called "Calories" and written with a capital C to distinguish them from little 'c' calories). Carbohydrates and proteins provide 17 kJ approximately (4 kcal) of energy per gram, while fats provide 37 kJ (9 kcal) per gram., though the net energy from either depends on such factors as absorption and digestive effort, which vary substantially from instance to instance. Vitamins, minerals, fiber, and water provide energy, but are required for other reasons. A third class of dietary material, fiber (i.e., non-digestible material such as cellulose), is also required, for both mechanical and biochemical reasons. Molecules of carbohydrates and fats consist of carbon, hydrogen, and oxygen atoms. Carbohydrates range from simple monosaccharides (glucose, fructose, galactose) to complex polysaccharides (starch and fiber). Fats are triglycerides, made of assorted fatty acid monomers bound to a glycerol backbone. Some fatty acids, but not all, are essential because they cannot be synthesized in the body. Protein molecules contain nitrogen and often sulfur in addition to carbon, oxygen, and hydrogen. The fundamental components of protein are nitrogen-containing amino acids, some of which are essential. Some of the amino acids are convertible (with the expenditure of energy) to glucose in a process known as gluconeogenesis. By breaking down existing protein, some glucose can be produced internally; the remaining amino acids are discarded, primarily as urea in urine.. This occurs normally only during prolonged starvation..

Other micronutrients include antioxidants and phytochemicals, which are said to influence (or protect) some body systems. Their necessity is not as well established as it is for vitamins and minerals. Most foods contain a mix of some or all of the nutrient classes, together with other substances, such as toxins of various sorts. Some nutrients can be stored internally (e.g., the fat soluble vitamins), while others are required more or less continuously. Poor health can be caused by a lack of required nutrients or, in extreme cases, too much of a required nutrient. For example, both salt and water (both absolutely required) will cause illness or even death in excessive amounts. Carbohydrate Carbohydrates include sugars, starches and fiber. They constitute a large part of foods such as rice, noodles, bread, and other grain-based products. Carbohydrates may be classified chemically as monosaccharides, disaccharides, or polysaccharides depending on the number of monomer (saccharide or sugar) units they contain. Monosaccharides, disaccharides, and polysaccharides contain one, two, and three or more sugar units, respectively. Polysaccharides are often referred to as complex carbohydrates because they consist of long, sometimes branched chains of single sugar units. Mono- and disaccharides are called simple carbohydrates. Dietary advice frequently but erroneously suggests that complex carbohydrates are superior to simple because they take longer to digest and absorb. Simple carbohydrates, on the other hand, are said to cause a spike in blood glucose levels rapidly after ingestion. These claims are false. In fact, many digestible polysaccharides are processed as rapidly as simple sugars in the human body. On the other hand some simple carbohydrates (fructose, for example) are processed in a different way and do not spike blood sugar. Thus the distinction between "complex" and "simple" does not predict the nutritional value or impact of carbohydrates. A better way of determining what effect particular foods may have on blood sugar and ultimately on health in general is the glycemic index. Carbohydrates are not essential nutrients but are typically an important part of the human diet. While it would not be accurate to categorize all carbohydrates as "bad" nutritionally, some carbohydrate sources may well have deleterious effects on health, especially when consumed in large quantities. Highly processed carbohydrates (sugars and starches) as well as fructose consumed in large quantities have been implicated in negative health outcomes. Insufficient carbohydrate consumption can result in the production of ketones in the body. Ketones are formed when the body does not have sufficient glucose to fully metabolize fats. Dietary fiber Dietary fibre is a carbohydrate (or a polysaccharide) that is incompletely absorbed in humans and in some animals. Fiber supplies 1.5 to 2.5 calories per gram, less than the 4 calories per gram provided by non-fibre carbohydrates. Dietary fibre from plants consists mainly of cellulose, a large carbohydrate polymer that is indigestible because humans do not have the required enzymes to disassemble it. There are two subcategories: soluble and insoluble fibre. Whole grains, fruits (especially plums, prunes, and

figs), and vegetables are good sources of dietary fibre. There are many health benefits of a high-fibre diet. Dietary fiber helps reduce the chance of gastrointestinal problems such as constipation and diarrhea by increasing the weight and size of stool and softening it. Insoluble fibre, found in wholewheat flour, nuts and vegetables, especially stimulates peristalsis -- the rhythmic muscular contractions of the intestines which move digesta along the digestive tract. Soluble fibre, found in oats, peas, beans, and many fruits, dissolves in water in the intestinal tract to produce a gel which slows the movement of food through the intestines. This may help lower blood glucose levels because it can slow the absorption of sugar. Additionally, fibre, perhaps especially that from whole grains[vague], is thought to possibly help lessen insulin spikes, and therefore reduce the risk of type 2 diabetes. The link between increased fibre consumption and a decreased risk of colorectal cancer is still uncertain. The Role Of Carbohydrates In The Body Five subheadings follow in this lesson subdivision, but there is actually only one basic role of carbohydrates in the human diet: to supply energy. It should always be kept in mind that carbohydrates or calories alone cannot adequately supply our energy needs, for we must have our carbohydrates in combination with other needs, such as proteins, water, vitamins, minerals, fats, etc. This means that a diet of refined sugar, refined rice, flour products and other "food fragments," though it supplies calories, cannot satisfactorily comprise the bulk of anyone's diet. A person on such a diet would suffer many problems, for the organism is not capable of living long or well on bare carbohydrates alone. They must be obtained in combination with the other essential food factors to be truly useful in the overall energy production and nutrition of the organism.

Carbohydrates Supply Energy

The body uses carbohydrates directly from the monosaccharide glucose. Glucose is in the blood and extracellular fluids (lymph) and can be made from glycogen. Glycogen is stored in the liver and muscles and in smaller amounts in the other organs and tissues of the body. Energy is derived from glucose by the splitting of the glucose molecules into smaller compounds and oxidizing these to form water, which frees quite a large amount of energy.

When carbohydrates needed for the functioning of the central nervous system, the muscles and the other body systems and functions are insufficient in the diet (as during a fast or on a weight-loss diet), stored adipose tissue (fat) is broken down into glucose to make up the caloric deficit. Some amino acids, instead of being used to make proteins, are deaminated and used as carbohydrates to supply energy. The formation of glucose from amino acids is called gluconeogenesis. This phenomenon enables one to maintain normal blood sugar levels during a fast.

Practically the entire fat store of the body can be used up without detriment to health. Because of this fact, and the fact that the body can also create carbohydrates from amino acids, fasting is a very safe practice from the standpoint of maintenance of normal blood sugar levels, of normal neurological functioning and of meeting all the body's various energy needs.

Carbohydrates Provide Fuel for the Central Nervous System

Nerve cells are very dependent upon glucose for their functioning. According to physiology texts, the glycogen in nervous tissues remains constant and is not mobilized for conversion to glucose. When insufficient carbohydrates are consumed to meet the energy needs of the central nervous system, besides the occurrence of gluconeogenesis, another phenomenon occurs during a fast of three weeks or more: The cells of the central nervous system adapt their metabolic apparatus to use ketone bodies in place of glucose. (Ketone bodies are substances synthesized by the liver as a step in the metabolism of fats.) The nerve cells obtain their needed functional energy from these metabolites. This explains why patients with blood sugar problems (diabetes or hypoglycemia) do not suffer ill effects during a fast. In fact, they benefit by fasting.

Carbohydrates Provide Fuel for the Muscular System Carbohydrates provide the major fuel for muscular exercise. Fats and proteins can be used only indirectly—by first being converted into carbohydrates. For this reason, a proper diet should consist primarily of carbohydrates—not primarily of proteins and fats as are commonly consumed in conventional nonvegetarian (and some lacto- and lacto-ovo vegetarian) diets.

The muscles use the glycogen present in the muscle cells and glucose in the bloodstream. However, glycogen from the muscles is more efficiently used than glucose because the breakdown of glycogen for use does not require energy input at the time, whereas a certain amount of energy is used to bring the blood sugar into the metabolic system of the muscles. (It does require energy to build up the glycogen supply in the first place, but this happens during periods of rest when plenty of energy is available.) If a diet high in carbohydrates is not consumed, tremendous muscular exertion over long periods and/or extreme and prolonged stress (as being stranded for weeks in Antarctica) can result in accelerated breakdown of body protein and stored body fat. The protein breakdown is evidenced by an increased excretion of nitrogen in the urine, and the fat breakdown is evidenced by a rise in the level of ketone bodies in the urine and in the blood. The blood sugar level is simultaneously lower.

when used as fuel. This is true.
What is being said in the textbooks is that proteins consumed will be used for tissue building and maintenance rather than being used as an emergency source of energy as long as the carbohydrate intake is sufficient. It is. that they are an inevitable part of life that will and must occur unless prevented by the proper nutrients. The remaining portion is used for the conversion of these molecules into suitable fuel. therefore. We will then be prepared to expend energy for longer and more strenuous exercise— whether it be in an emergency or in pursuing pleasure. Vitamin C supplies body needs." However. 2) An appropriate balance between supplying body needs (such as rest and carbohydrates) and expending energy (muscular.
"Sparing proteins" is not a separate and distinct function or role of carbohydrates any more than preventing scurvy is a separate and distinct function of vitamin C in the body. Besides. nervous or other) should be strived for to attain optimum health and well-being. That is a backwards way of viewing health—it's the disease approach. which supply the body's organs with fuel via the bloodstream. etc. The fact that the body can and will use body fats and proteins when the supply and stores of blood sugar and glycogen are not great enough to meet the demand for energy exemplifies two facts: 1) The organism is provident. Carbohydrates Supposedly Spare Proteins Physiology textbooks refer to this so-called role or function of carbohydrate in the body as "its proteinsparing action. It is stating the true fact that carbohydrates. yield less than their total caloric value in the form the muscles can use. "sparing protein" is not a function or role of carbohydrates at all. This conversion takes place in the liver and adipose tissue. beneficial to do regular vigorous exercise to increase our storage of muscle glycogen. Just as good things happen to us if we think positive thoughts and visualize success. It has many back-up arrangements for survival in emergency situations when sufficient carbohydrates are not available. but it is only another way of saying that carbohydrates are the primary and most efficient source of energy or fuel and that it is best not to try to meet our fuel needs from proteins. harmony. not proteins. it is incorrect to attribute action (other than chemical action) to carbohydrates or other inanimate substances. It has been found that people who are accustomed to doing prolonged or strenuous work have larger stores of glycogen (and of phosphate esters) in their muscles than those not accustomed to much physical activity. Carbohydrates simply furnish our fuel or energy needs—and nothing more.The body works much more efficiently from carbohydrate intake than from broken-down body protein and fats because protein and fat molecules. Viewing nutrients as preventative agents of diseases is another way of saying that diseases are normal.. but its role is not prevention of scurvy or of anything else. supply our primary nutrient needs. or the medical approach. good health will exist as long as we live
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(Fiber [cellulose] is one of those missing parts. it cannot be utilized by the body as a nutrient. The ingestion of too many toxins from all sources. What is significant is how much and what kinds of toxins are there (and elsewhere). Based on the high correlation between low-fiber diets and human gastrointestinal diseases. though in fact a carbohydrate because it is utilized as such by herbivores. as well as the retention of toxic wastes produced within the body. Cellulose is known to be indigestible by humans.healthfully—and that includes consuming the correct amounts of the foods to which we were biologically adapted in nature to eat. nor do we deny the fact that people who consume diets closer to nature and therefore higher in fiber (cellulose) have fewer gastrointestinal diseases and a lower rate of bowel cancer. Carbohydrates Supposedly Supply "Dietary Fiber" "Dietary fiber" is a fairly new term coined to describe the cellulose inside plant cells. highly-refined. Its presence or absence in the feces is insignificant. However.
It has been observed that certain so-called primitive tribes in Africa and elsewhere who consume diets high in fiber are less likely to develop certain colon diseases and metabolic disorders than their kinsmen who live in urban areas and eat low-fiber foods similar to those consumed in so-called developed countries. so-called foods (they do contain carbohydrates) do not deserve the label foods because they are not whole foods. We do not deny that high-fiber diets are more wholesome as a rule than low-fiber diets. Parts of processed foods are missing—they were removed intentionally in the refining process.
In short. many hospitals and clinics have changed their dietary management of diverticulosis. Because it cannot be digested and utilized by humans. it cannot provide us with energy—and providing energy is the only role of carbohydrates in human nutrition. They are experiencing good results with a diet containing more instead of less cellulose. What we argue against is the thinking that the fiber itself is primarily responsible for the prevention of these diseases and disorders. results in diseases. does not serve the role of a carbohydrate in human physiology. the so-called "protein-sparing action" of carbohydrates is not only not an action. but sparing proteins is not a distinct role of carbohydrates separate from their energy-providing role.
The above statements may come as a surprise to most readers—but read on and we'll clarify further. though it is digested and used for energy by herbivores. It is simply passed through with the other wastes. The presence or absence of indigestible plant fibers does not prevent or cause diseases. Since cellulose is indigestible. cellulose. Processed. The claims made about "the beneficial role of dietary fiber in preventing diseases" are so popular and so widely made that they are practically accepted as fact.) This makes them
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etc. calcium and other minerals. as well as refined flour products. how much is eaten. but this has been discussed in previous lessons and will also be further discussed in future lessons. Because the refined products are devoid of nutrients except carbohydrates. incompatible food combinations result in the production of toxins in the stomach and elsewhere in the digestive tract. these products are like drugs within the body. There is a group of disease. they should not be eaten. Being devoid of vitamins and minerals in their natural form (the only form they can be used in). Rare disorder and is characterized by the following features-
Hurler syndrome-Head appears large with prominent forehead and puffy eyelids -Nasal congestion with noisy breathing -Shortening and broadening of the mandible with wide intergonial . must be utilized by the body to metabolize refined products. but there are many. Refined sugar and products containing refined sugar. flours. it is sufficient for us to explain that low-fiber diets not only lack the natural cellulose which should be left intact in the whole food.Dentition-small and misshaped teeth. (Of course. Refined sugar. fresh air. foods not normal to humans. white rice and processed cereals are some of the worst culprits. For now.incomplete or fragmented foods. Also. Most "civilized" diets contain cooked foods. are the most salient examples of processed food fragments that produce toxic effects in the body. Much more could be said about the sources of toxins within the body that result in disease. distance
. calcium is taken from the bones. and these toxins also contribute to gastrointestinal disturbances and diseases. In addition. but they also contain or give rise to a host of toxins that result in disease conditions. which represents a primary genetically determined disturbance of the mucopolysaccharide metabolism. refined and processed foods and drugs and medications.) Deficiency of carbohydratesAlmost nothing is known of the effect of carbohydrate deficient diet on the oral cavity. indulged are also important factors in human nutrition. many more sources of toxins in the diet.Increased arch length from ramus to ramus . It is not the lack of fiber itself that causes diverticulosis and other gastrointestinal problems but the overall unwholesomeness of the foods ingested in so-called civilized society. Eating fragmented foods results in problems in the body.. Therefore. as well as B vitamins. sleep. the amount of exercise. you should understand that what is eaten is only part of the picture and that how it's eaten.

Trans fats are very rare in nature.g. Furthermore. these are rare in nature and in foods from natural sources. such as rancidity resistance. Unsaturated fats may be further classified as monounsaturated (one doublebond) or polyunsaturated (many double-bonds). whereas unsaturated fats have some of these carbon atoms double-bonded. or can be taken in directly through food. There are nine kilocalories in each gram of fat. The American Heart Association recommends limiting intake of all fats in the diet.. Saturated and some trans fats are typically solid at room temperature (such as butter or lard).. depending on the location of the doublebond in the fatty acid chain. generally from other fatty acids and always by expending energy to do so. so their molecules have relatively fewer hydrogen atoms than a saturated fatty acid of the same length. However. bonded to a glycerol.g. Both DGLA and AA can be made from the omega-6 linoleic acid (LA) in the human body. in some respects. weakly inflammatory PGE3). while unsaturated fats are typically liquids (such as olive oil or flaxseed oil). and have been shown to be highly detrimental to human health. which can be made in the human body from the omega-3 essential fatty acid alpha-linolenic acid (LNA). Fats may be classified as saturated or unsaturated depending on the detailed structure of the fatty acids involved.. An appropriate balance of essential fatty acids—omega-3 and omega-6 fatty acids—seems also important for health.-Soft tissue –gingival hyperplasia. people typically consume large amounts
. meaning the body can produce them as needed. They are hormones. An appropriately balanced intake of omega-3 and omega-6 partly determines the relative production of different prostaglandins. Saturated fats (typically from animal sources) have been a staple in many world cultures for millennia. In industrialized societies.g. but have properties useful in the food processing industry. vegetable oil) intake. Both of these "omega" long-chain polyunsaturated fatty acids are substrates for a class of eicosanoids known as prostaglandins. Trans fats are a type of unsaturated fat with trans-isomer bonds. anti-inflammatory PGE1). but particularly advises keeping saturated and trans fat intake below the level of unsaturated fat (e. although definitive experimental demonstration has been elusive. whereas arachidonic acid (AA) serves as a building block for series 2 prostaglandins (e.g. they are typically created in an industrial process called (partial) hydrogenation. in humans. pro-inflammatory PGE 2). which is one reason why a balance between omega-3 and omega-6 is believed important for cardiovascular health. Essential fatty acids Most fatty acids are non-essential. The omega-6 dihomo-gamma-linolenic acid (DGLA) serves as a building block for series 1 prostaglandins (e. The omega-3 eicosapentaenoic acid (EPA). which have roles throughout the human body. Saturated fats have all of the carbon atoms in their fatty acid chains bonded to hydrogen atoms. Fat A molecule of dietary fat typically consists of several fatty acids (containing long chains of carbon and hydrogen atoms). at least two fatty acids are essential and must be included in the diet. serves as a building block for series 3 prostaglandins (e. or taken in through marine food sources.. They are typically found as triglycerides (three fatty acids attached to one glycerol backbone). unsaturated fatty acids are classified as omega-3 or omega-6 fatty acids.

until such time as the offending substances can be metabolized and/or removed from the body by such means as excretion. This helps to protect vital organs. and hair growth. The body requires
. along with some types of amino acid. which in turn is controlled by hormones such as insulin (up-regulation) and glucagon (down-regulation). and mitosis (i. insulating body organs against shock. containing about 37. an important dietary requirement. glucagon. such as the keratin in hair). meaning they can only be digested. Fats are also sources of essential fatty acids. accidental or intentional bloodletting. and promoting healthy cell function. and transported in conjunction with fats. They are broken down in the body to release glycerol and free fatty acids.e. Each molecule is composed of amino acids. E. Fat also serves as a useful buffer towards a host of diseases.g. The glycerol can be converted to glucose by the liver and thus used as a source of energy. meaning that they can't be produced in the body from other compounds and need to be consumed in small amounts. All other fats required by the body are nonessential and can be produced in the body from other compounds. absorbed. They also form the enzymes that control chemical reactions throughout the body.. cell division). the body can effectively dilute—or at least maintain equilibrium of—the offending substances by storing it in new fat tissue. therefore the ratio of omega-3 versus omega-6 has wide effects on general health. The amount and type of carbohydrates consumed. it would also be unhealthy to do so. Omega-3 EPA prevents AA from being released from membranes. Fats play a vital role in maintaining healthy skin and hair. and other hormones. muscles. While it is nearly impossible to remove fat completely from the diet.
Protein Proteins are the basis of many animal body structures (e. maintaining body temperature. and specific effects on immune function and inflammation. When a particular substance.8 kilojoules (9 Calories) per gram of fat. Moreover. D. the conversion (desaturation) of DGLA to AA is controlled by the enzyme delta-5-desaturase. and K are fat-soluble. whether chemical or biotic—reaches unsafe levels in the bloodstream. The conversion rate of omega-6 DGLA to AA largely determines the production of the prostaglandins PGE1 and PGE2. can influence processes involving insulin. thereby skewing prostaglandin balance away from pro-inflammatory PGE2 (made from AA) toward anti-inflammatory PGE1 (made from DGLA). and hair). Importance of fats in living organisms Vitamins A. which are characterized by inclusion of nitrogen and sometimes sulphur (these components are responsible for the distinctive smell of burning protein. which have reduced amounts of the essential fatty acids along with too much of omega-6 fatty acids relative to omega-3 fatty acids. sebum excretion. Fats also serve as energy stores for the body. skin. Some fatty acids are essential nutrients. urination.of processed vegetable oils.

pregnancy. The term "mineral" is archaic. and oxygen that are present in nearly all organic molecules. There are innumerable functions of proteins in the body. Well. other than the four elements carbon. hydrogen. Sources of dietary protein include meats. Functions of Proteins in the Body Proteins play a major role in ensuring your health well being. A complete protein source contains all the essential amino acids. The rest part of proteins is in the other body tissues and fluids. for instance).. There is a constant breakdown of proteins in the body and this explains the reason why we need to consume proteins on a regular daily basis. therefore. There are distinctive kinds of proteins. next to water. Twenty-one proteinogenic amino acids are found in the human body. since the intent is to describe simply the less common elements in the diet. along with non-proteinogenic amino acids (e. Dietary minerals Dietary minerals are the chemical elements required by living organisms. It becomes of prime importance to ensure that you have your daily-recommended protein intake. eggs. must be included in the diet. Our body requires proteins for the purpose of maintenance and healthy growth. and dairy products such as milk and cheese. regulation of body processes and formation of enzymes and hormones. The need for consuming proteins is especially more for infants. typically in the urine. The amino acids remaining after such conversion are discarded. lactation. Excess amino acids from protein can be converted into glucose and used for fuel through a process called gluconeogenesis. young children. so as to improve your health fitness. nitrogen. legumes.g. Proteins form a major part of your body. The composition of proteins in the body is like that muscle contains about 1/3 protein. Excess amino acids are discarded.amino acids to produce new proteins (protein retention) and to replace damaged proteins (maintenance). some amino acids are essential (an animal cannot produce them internally) and some are non-essential (the animal can produce them from other nitrogen-containing compounds). Proteins serve as a major energy supplier. A diet that contains adequate amounts of amino acids (especially those that are essential) is particularly important in some situations: during early development and maturation. each performing a unique function in the body. gamma-aminobutyric acid). an incomplete protein source lacks one or more of the essential amino acids. tofu and other soy-products. In fact the hemoglobin molecule is nothing but proteins. Even blood contains loads of proteins. amino acids must be present in the diet. the primary functions of proteins include building and repairing of body tissues. For all animals. bone about 1/5 part and skin consists of 1/10 portion. Some
. As there is no protein or amino acid storage provision. Read further to explore information about protein role in health…
Proteins aid in the formation of antibodies that enable the body to fight infection. Ten of the proteinogenic amino acids are essential and. or injury (a burn. pregnant women and recovering patients.

despite being needed in large quantities. Macrominerals Many elements are essential in relative quantity.[19] Some trace mineral elements (RDA < 200 mg/day) are.. very common electrolyte. but in the form of sulfur-containing amino acids Trace minerals Many elements are required in trace amounts. Some dietitians recommend that these be supplied from foods in which they occur naturally. and pancreas). may help clear toxins. Sulfur is not consumed alone. a common electrolyte.[verification needed] which has been shown can lead to high blood pressure and osteoporosis (Note: Some sources suggest high blood pressure is due to high water retention per osmosis). below Magnesium. in alphabetical order (with informal or folk-medicine perspectives in parentheses): Calcium. or common salt. liver. Excessive sodium consumption can deplete calcium and magnesium. Some minerals are absorbed much more readily in the ionic forms found in such sources. Some are structural. essential for energy processing[18] Potassium. Animals cannot biosynthesize B12. and must obtain this cobalt-containing vitamin in the diet Copper required component of many redox enzymes. including cytochrome c oxidase Chromium required for sugar metabolism
. bone strength. including several metals. a very common electrolyte. required for processing ATP and related reactions (builds bone. required component of bones. because the ion is very common in food: typically as sodium chloride. increases alkalinity) Phosphorus. some forms neutralize acidity. a very common electrolyte (heart and nerve health) Sodium (also see salt). they are usually called "bulk minerals".Elements with recommended dietary allowance (RDA) greater than 200 mg/day are. usually because they play a catalytic role in enzymes. Sulfur. which often occur as ions in the body. hair. for three essential amino acids and therefore many proteins (skin. not generally found in dietary supplements. causes strong peristalsis. the most famous is likely iodine in iodized salt which prevents goiter. see sodium. increases flexibility. provides signaling ions for nerve and membrane functions) Chlorine as chloride ions. in alphabetical order: Cobalt required for biosynthesis of vitamin B12 family of coenzymes. or sometimes even from natural inorganic sources (such as calcium carbonate from ground oyster shells). nails. but many play a role as electrolytes.are heavier than the four just mentioned. or at least as complex compounds. On the other hand. but also needed structurally (for muscle and digestive system health. minerals are often artificially added to the diet as supplements.

growth retardation. defective keratinization and pigmentation of hair. nephrolithiasis. salivary glands.Fluoride required for maintenance of bone structure Iodine used by the thyroid gland to produce thyroid hormone (thyroxine and triiodothyronine). No specific biochemical function has been identified for it in humans. Renal insufficiency (milk-alkalai 2500 mg/d (milksyndrome). diarrhea. testicular atrophy from animal data) mass. degenerative
. vomiting. tremor. and for hemoglobin and some other proteins Manganese (processing of oxygen) Molybdenum required for xanthine oxidase and related oxidases Nickel present in urease Selenium required for peroxidase (antioxidant proteins) Vanadium (There is no established RDA for vanadium.) Zinc required for several enzymes such as carboxypeptidase. renal dysfunction
Calcium
Reduced bone osteoporosis
Copper
Anemia. for this reason iodine may be needed in larger quantities than others in this list Iron required for many enzymes. alkalai) impaired iron absorption Nausea. breast. and carbonic anhydrase
Table 71-2 Deficiencies and Toxicities of Metals
Element
Deficiency
Toxicity
Tolerable Upper (Dietary) Intake Level
Boron
No biologic determined
function Developmental defects. hemolytic anemia. 10 mg/d (liver hepatic failure. mental toxicity) deterioration. liver alcohol dehydrogenase. male 20 mg/d (extrapolated sterility. hypothermia. and stomach (see Extrathyroidal iodine and Iodine and cancer risk. may also be used by other important organs such as the thymus. although vanadium is required for some lower organisms.

symptoms of premature aging. dermatitis. sweating. Deficient or excess levels of minerals can also have serious health consequences. are thought useful for survival and health. which may have desirable properties including antioxidant activity (see below). GI. paresthesia. seizure. impaired immune system. Certain vitamin-like compounds that are recommended in the diet. Hyperphosphatemia proximal muscle weakness. immune dysfunction. certain forms of cancer. osteoporosis. confusion. scurvy. taste and smell. but these are not "essential" dietary nutrients because the human body has some capacity to produce them from other compounds. vomiting metabolism) Occupational: Respiratory distress. gastrointestinal. essential fatty acids (see above). experimental demonstration has been suggestive but inconclusive. choline. disorders of cell metabolism. congenital malformations Note: ND. failure to thrive. including goitre. alopecia. hemolysis. diarrhea. however. in the presence of UVB radiation. Vitamin deficiencies may result in disease conditions. and poor psychological health (including eating disorders). and for at least one vitamin. gonadal atrophy. heart failure. ataxia. such as carnitine. B6.
General: Reduced copper 40 mg/d absorption. gastritis. Moreover. acidosis 4000 mg/d
Zinc Growth retardation. Other essential nutrients that are not classified as vitamins include essential amino acids (see above). rhabdomyolysis.
.[20] Excess levels of some vitamins are also dangerous to health (notably vitamin A). necessary in the diet for good health. thousands of different phytochemicals have recently been discovered in food (particularly in fresh vegetables). nausea. pulmonary fibrosis
Vitamins As with the minerals discussed above. (impaired copper fever. not determined.pulmonary inflammation Phosphorous Rickets (osteomalacia). Vitamin D is the exception: it can be synthesized in the skin. toxicity begins at levels not far above the required amount. among many others. and the minerals discussed in the preceding section. some vitamins are recognized as essential nutrients.

Vitamin D is a group of fat-soluble compounds collectively known as the calciferols. Vitamin A–deficient individuals develop night blindness and skin lesions. a disorder of normal bone ossification manifested by distorted bone movements during muscular action. Vitamin D is essential for normal development and growth and the formation of bones and teeth. Vitamin A is important in the production and regeneration of rhodopsin of the retina and in the normal growth of the skin. Vitamin D. The principal form of vitamin A is retinol.Vitamin A. the aldehyde (retinal) and the acid (retinoic acid) are also active forms of vitamin A.
. Retinol can be derived directly from animal sources or through conversion from carotene (found abundantly in carrots) in the small intestine. Vitamin D deficiency can result in rickets. Vitamin D3 (also called cholecalciferol or activated dehydrocholesterol) in the human body is derived from two main sources: the skin. which contains a rich source of 7-dehydrocholesterol that is rapidly converted to cholecalciferol when exposed to UV light. and dietary vitamin D3.

as well. which like other steroid hormones has its receptors within the cytosol of cells. 1989). fatigue. The Water-Soluble Vitamins Are C. 1. Contrarily. Vitamin K is essential for the synthesis of various clotting factors by the liver. Vitamin E. Osteoblasts .. by increasing the number of osteoclasts. The D3 receptors are found ubiquitously in all tissues.25(OH)2D3 reacts specifically on bone. It increases the size of the ruffled border. The receptor-D3 complex is transferred to the nuclear DNA for specific gene transcription (Heddad.1 987). Vitamin B1. 1986. has an effect on all cells of bone either directly or indirectly.25(OH)2D3 increases the ability of intestinal resorptive cells to absorb Ca++ (Reichel et al. This then. B12. Cholecalciferol from skin is hydroxylated in the 25 position in the liver and in the 1 position in the kidney..
. although it targets other organs involved with mineral metabolism such as kidneys. to inhibit T-cell gamma interferon which in turn is a potent inhibitor of osteoclast stimulatory activity. B1. Vitamin K deficiency is associated with bleeding disorders. Niacin. B2. It plays an important role in many oxidative processes by acting as a coenzyme or cofactor. l9g3). and bone lining cells all have 1. It plays a roll. parathyroids.25(OH)2D3 receptors indicating a predelective site on osteoblasts and implying a direct effect on bone production by bone producing cells. and Folic Acid Vitamin C. an increase in nucleii indicating coalescence of monocytes and an increase of osteoclastic lysosomal enzymes. osteoprogenitor cells. Vitamin B1 (thiamine) plays an important role in carbohydrate metabolism. Biotin. Vitamin C deficiency is associated with scurvy. The resultant effect of all this activity is for 1. Tocopherol deficiency is associated with increased red cell susceptibility to lipid peroxidation.. Vitamin K can be derived from green vegetables in the diet or the gut flora.25(OH)2D3to increase osteoclast activity and bone resorption.1 988). and bleeding gums.25(OH)2D3 deficiency leads to decreased bone formation with an increase in non-mineralized osteoid.1 . but not in mature osteoclasts in vivo which could indicate that osteoclast precursor cells are activated but not the mature osteoclasts( Merke et al. and small intestines (Reichel et al.This favors osteogenesis by increasing plasma Ca++ ions and the concentration gradient pathway of Ca++ into the extracellular bone compartment. 1'25(OH)2D3 might activate osteoclasts by prodding osteoblasts and immune system cells to secrete osteoclast activating substrates( McSheehya nd Chambers. osteoblast-like cells. B6. 1. causes a net increase of Ca++ ions into the circulation and a potential increase of bone formation. anemia. Thiamine deficiency results in beriberi. Vegetable oils are rich in vitamin E. which may explain why the red cells are more fragile in vitamin E–deficient individuals than in healthy individuals. characterized by anorexia and disorders of the nervous system and heart. Vitamin K. Vitamin E is a potent antioxidant and therefore prevents lipid peroxidation. is a steroid hormone. Narbeitz et al. 1. The major source of vitamin C (ascorbic acid) is green vegetables and fruits. 1989). a disorder characterized by weakness. It is a potent stimulator of resorptive activity. 1'25 (OH)2D3 increases calcitonin receptors on multinucleated giant cells in bone marrow cultures (Takahashi.25(OH)2D3 with endocrine or paracrine function. The major dietary vitamin E is _-tocopherol.ROLE OF VITAMIN D3 ON BONE : Active vitamin D. 1987). Concomitantly. Indirectly..

Vitamin B12. The original water intake recommendation in 1945 by the Food and Nutrition Board of the National Research Council read: "An ordinary standard for diverse persons is 1 milliliter for each calorie of food. It decreases plasma total cholesterol and LDL cholesterol. which play an important role in the metabolism of lipids. Vitamin B6 . and growth. dermatological lesions. Biotin acts as a coenzyme for carboxylase. and amino acids.The notion that a person should consume eight glasses of water per day cannot be traced to a credible scientific source. Niacin plays an important role as a component of the coenzymes NAD(H) and NADP(H). Biotin. A deficiency of this vitamin is often associated with anemia and CNS disorders. and nervous disorders. Niacin deficiency is characterized by many clinical symptoms. Niacin.
Water It is not fully clear how much water intake is needed by healthy people. Vitamin B6 (pyridoxine) is involved in amino acid and carbohydrate metabolism. Vitamin B2 (riboflavin) is a component of the two groups of flavoproteins—flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN). a disease characterized by dermatitis. and diarrhea. Riboflavin plays an important role in metabolism. greater or lesser. in its most severe form. and decarboxylase enzymes. Severe deficiency leads to pellagra. yet increases plasma HDL cholesterol. It is required for the formation of nucleic acids. A glycoprotein secreted by the parietal cells in the stomach called the intrinsic factor binds strongly with vitamin B12 to form a complex that is then absorbed. Biotin is so common in food that deficiency is rarely observed. transcarboxylase. water intake on weight loss and on constipation is also still unclear. The discovery of vitamin B12 (cobalamin) followed from the observation that patients with pernicious anemia who ate large quantities of raw liver recovered from the disease. including anorexia. Folic acid deficiency causes a fall in plasma and red cell folic acid content and. the development of megaloblastic anemia. and skin eruptions.Vitamin B2. Individuals who lack the intrinsic factor fail to absorb vitamin B12 and develop pernicious anemia. which participate in a wide variety of oxidation-reduction reactions involving H_ transfer. which plays an important role in the production of red blood cells. Folic acid is usually found in the diet as polyglutamyl conjugates (pteroylpolyglutamates). the maturation of red blood cells. Folic Acid. for the prevention of coronary artery disease. Subsequent analysis of liver components isolated the cobalt-containing vitamin. Riboflavin deficiency is associated with anorexia. Most of this quantity is contained in prepared foods. impaired use of food. Niacin has been used to treat hypercholesterolemia. although some assert that 6–7 glasses of water daily is the minimum to maintain proper hydration." The latest dietary reference intake report by the United States National
. impaired growth. Vitamin B12 is transported in the portal blood bound to the protein transcobalamin. The effect of. and poor growth. glucose. indigestion. muscle weakness. dementia.

Moderate dehydration can cause headaches and dizziness. acceptors of electrons) and some react very strongly.11. pregnant and breastfeeding women need additional fluids to stay hydrated. including urine and feces. For the continued normal cellular maintenance. Bones are 22% water.7 liters for men. Removes waste. generally. Regulates body temperature. Vitamin C is water soluble and protects those areas).5 cups) because an especially large amount of fluid is lost during nursing.. sweating.bottledwater.Research Council recommended. Helps to convert food into energy. while the rest comes from drinking water and assorted beverages. some antioxidants produce a different free radical compound that is less dangerous or more
. polyphenols.7 liters of water total for women and 3.g.In particular. about 4.9. Helps body absorb nutrients. these free radicals must be sufficiently neutralized by antioxidant compounds. about 20 percent of water intake comes in food.12. Vitamin C can reactivate free radicalcontaining glutathione or Vitamin E by accepting the free radical itself. Water is excreted from the body in multiple forms. the International Bottled Water Association (IBWA at www.000 are known. it is somewhat difficult to drink too much water. Vitamin K) or produced by the body from other compounds (beta-carotene is converted to Vitamin A by the body. Some are produced by the human body with adequate precursors (glutathione. Carries nutrients and oxygen to all cells in the body. Some antioxidants are more effective than others at neutralizing different free radicals. Protects and cushions vital organs. Muscles are 75% water. To help understand importance of water in the body..2 litres and men 3.3. potentially damaging (e. Water is required for expiration. and those the body cannot produce may only be obtained in the diet via direct sources (Vitamin C in humans. it is also possible to drink far more water than necessary which can result in water intoxication. on average.6.. When interacting with a free radical. Phytochemicals (below) and their subgroup.but (especially in warm humid weather and while exercising) it is dangerous to drink too little. Blood is 92% water. Moistens oxygen for breathing. Vitamin A.7. For example. Some cannot be present in certain areas of free radical development (Vitamin A is fat-soluble and protects fat areas. While overhydration is much less common than dehydration.4. 12.2.13. and division. Brain is 75% water. Cushions joints Antioxidants As cellular metabolism/energy production requires oxygen. large amounts of de-ionized water are dangerous.e. Normally.. Most of these are oxidizers (i.4 litres (approx. Specifically.5... women consume 2. Vitamin C). growth.. make up the majority of antioxidants. (including food sources): 2.8. a serious and potentially fatal condition. and water vapor in the exhaled breath. mutation causing) compounds known as free radicals can form.0 litres of water daily—advises pregnant women consume 2. Some cannot neutralize certain free radicals.org) lists 13 things water does in the body: 1. Different antioxidants are now known to function in a cooperative network..[26] For those who have healthy kidneys.[29] and Vitamin D is synthesized from cholesterol by sunlight). The Institute of Medicine—which recommends that. 9 cups) and breastfeeding women consume 3 litres (approx.10.

Yet. translating it to practical dietary advice can be difficult and counter-intuitive. Lutein. appears to protect against chronic joint inflammatory diseases. Perhaps the most rigorously tested phytochemical is zeaxanthin. a yellow-pigmented carotenoid present in many yellow and orange fruits and vegetables. but also other organisms including seafood. beta-cryptoxanthin. lutein. Although initial studies suggested that antioxidant supplements might promote health.dangerous than the previous compound. Another carotenoid. in some cases. key chemicals in cardiovascular disease. While the association between serum blood levels of beta-cryptoxanthin and substantially decreased joint disease has been established. occurs in many yellow and orange fruits and vegetables and protects the eyes against various diseases.. neither a convincing mechanism for such protection nor a cause-and-effect have been rigorously studied. especially colorful fruits and vegetables. Less rigorous studies have proposed a correlation between zeaxanthin intake and cataracts. The effects of phytochemicals increasingly survive rigorous testing by prominent health organizations. Additionally. has also been shown to lower the risk of contracting AMD. and the presence of lutein in the retina will prevent zeaxanthin uptake. such as arthritis. evidence has shown that the lutein present in egg yolk is more readily absorbed than the lutein from vegetable sources. collectively called phytochemicals. a red phytochemical. lycopene. some of the correlations between the ingestion of certain phytochemicals and the prevention of disease are. later large clinical trials did not detect any benefit and suggested instead that excess supplementation may be harmful. the question "should you eat eggs?" is complex to the point of dismay. it does not protect the eye nearly as well as zeaxanthin. including misperceptions about the health effects of cholesterol in egg yolk. Similarly. Phytochemicals A growing area of interest is the effect upon human health of trace chemicals. and they serve to protect the rods and cones against the destructive effects of light. Having a variety of antioxidants allows any byproducts to be safely dealt with by more efficient antioxidants in neutralizing a free radical's butterfly effect. These chemicals are known to down-regulate the formation of reactive oxygen species. and its saturated fat content. These nutrients are typically found in edible plants. algae. Both compounds have been observed to collect in the retina when ingested orally.. As indicated above. and fungi. even when the evidence is obtained. possibly because of fat solubility.[35] At the most basic level.
. However. for example. A second carotenoid. chemicals that are known to provide certain health benefits to the cardiovascular system and immune system. enormous in magnitude. One of the principal classes of phytochemicals are polyphenol antioxidants. has substantial credible evidence of negative association with development of prostate cancer. Repeated studies have shown a strong correlation between ingestion of zeaxanthin and the prevention and treatment of age-related macular degeneration (AMD).

In conclusion. Mg and Zn in childhood have been calculated based on mineral deposition rates. or tomato soup. P and Zn are likely to produce rickets and growth retardation. Abstract The evidence on the relationship between dietary mineral supply and bone development in children has been extensively reviewed. such sauces tend to have high amounts of salt. in processed tomato products such as commercial pasta sauce. but are 4-5 times higher in older children. repressing the growth of harmful bacteria. Ca intakes at all ages were found to be close to the biological requirement for children in many Third World societies. before any allowance for possible poor absorption. sugar. stimulating cell growth. including breaking down and aiding in the absorption of otherwise indigestible food. Intestinal bacterial flora It is now also known that animal intestines contain a large population of gut flora. L. training the immune system to respond only to pathogens. Supplementation studies indicate that raising Zn intakes can increase height gains in certain vulnerable groups. other substances a person may wish or even need to avoid. and defending against some infectious diseases. discussion S177. This revealed that P and Mg intakes were many times higher than estimated needs. Prentice A. It is more highly concentrated. particularly during weaning. Cambridge. using published values for the mineral content of the human body. NUTRIENT RDA DEFICIENCY DOSEASE SOURCE
. however. the evidence suggests that inadequate dietary intakes of Ca and Zn may contribute to linear growth retardation in children of developing countries but more research is needed. MRC Dunn Nutrition Unit. Poor absorption from phytate-rich diets could affect Zn supply. The biological needs for Ca. while the effects of Mg deficiency on human bone are unknown. among many others. such as infant and adolescent boys. Bates CJ. UK.48 Suppl 1:S161-76. P. these include species such as Bacteroides. and are also affected by the food we eat. The manifestations of marginal deficiencies are little understood. Adequacy of dietary mineral supply for human bone growth and mineralisation. and E. 1994 Feb. P.
Eur J Clin Nutr. Yet. than in fresh "healthy" tomatoes. 100. the estimated biological requirements for the Ca. A comparison of measured daily intakes of children in developing countries with biological requirements was made. Data from children and primates suggest that overt deficiencies of Ca. Mg and Zn can be taken as 200. Bacteria in the gut perform many important functions for humans. As a rough guide. coli. In humans. Zn intakes approach estimated needs in breast-fed infants. and on obligatory endogenous losses. 4 and 1 mg/d respectively. acidophilus. lycopene is prevalent in tomatoes (and actually is the chemical that gives tomatoes their red color).As another example. They are essential to digestion. producing vitamin B12.

Therefore interferences with substrate availability results in decreased protein metabolic activity. However diet should be adapted to the special needs of growth. placenta is the provider of the essential nutrient substrates and fetal tissue synthesizes its own proteins and nucleic acids. amino acids. vitamins. Guilford in 1874 was amongst the first to advocate dietary deficiencies as an underlying cause of dentofacial irregularities. eggs.Vit. In constructing a balanced diet the dietary goals recommended by the WHO should be borne in mind: 1. lactation. vitality and general well being and also makes small provision for extra nutrients to withstand short duration of leanness. Critical periods are defined as that time in the development of an organ system which is marked by the rapid synthesis and accretion of protein. 20-30% of total daily intake 3. mucosal atrophy. Development is a process which commences at conception and continues through birth until death. Saturated fats should be avoided 4. minerals. The critical period roughly equates with the intense hyperplastic
. Carbohydrates rich in natural fibre should be taken. 15-20% of daily energy intake 2. The perceptible visible evidences of developmental changes is Growth. carbohydrates and other nutrients is adequately met for maintaining health. Protien should account for appox. Important relationship exists between diet and development which can be seen during the nutrition of the foetus.
BALANCED DIET A balanced diet is defined as one which contains a variety of foods in such quantities and proportions that the need for energy. kgloss it is Liver meat. Nutrition in Orthodontics
NUTRITION IN GROWTH AND DEVELOPMENT Nutrition plays a vital role in the growth and development of an individual. Excessive consumption of refined carbohydrates should be avoided 5. Dietary fats should be limited to approx. milk. pregnancy.B12 (Cyanocobalamin)
1 ug
Pernicious anaemia. fats. Miller suggested that “ critical periods” exist during the development of an organ and that stress imposed by the nutritional imbalance during critical periods can result in irreversible changes. physical activity and medical disorders.

Malnutrtion has also been associated with shorter mandibles in the antero posterior dimension.growth phase. a reduction in dimension of dental arches with inadequate space for teeth. Cleft lip and palate
. In animal studies. Increased Vitamin A also causes softening of the skull due to decrease in the calcium deposition. condylar region and the setting of the premolars. Animals fed on diets deficient in folic acid . dentoalveolar inclination in the incisor region and reduction in the mesio-distal dimension of the third molars. histologic and histo chemical studies have demonstrated such abnormalities in osseous tissues as the reduction of the cortex and enlargement of the medulary spaces and a weakening of the osteoblastic and osteoclastic activity. Dietary deficiencies of essential nutrients during the critical periods of growth have caused retardation of growth and morphologic alterations of the orofacial area in both humans and animals. transverse hypodimension and misshapen palate. Deficiencies of these nutrients cause retarded jaw . insufficient dental eruption. a high rate of bone growth can readily be demonstrated around the time of weaning when the animal changes from a relatively low protein to a high protein diet which is during the hyperplastic growth phase. have borne offsprings with increased risk of cleft lip and palate. Vitamin A defieciency which frequently accompanies protein calorie malnutrition may result in inadequate bone growth patterns with concomitant malalignment and malocclusion of the teeth. riboflavin and zinc . teeth and condyle development. Vitamin D and phosphorus are essential for the formation of bones and teeth. maxillary dysplasia. Even short periods of malnutrition (7-12 months) have resulted in an increase in open bites. Deficiency of Vitamin D causes rickets. It is important to point out that growing bone is different to mature bone in its response to the environment. marked reduction in the ascending ramus. Calcium. Radiologic. First the soft tissue matrix is laid down followed by the formation of the hard tissue components. Any nutritional deficiency occurring during the active growth can be disastrous. succeptibility to muscular traction. It has been shown in animal studies that certain hormones like the pituitary hormone are sensitive to nutritional deficiencies. An excess of vitamin A during the critical growth period markedly inhibits the neural crest cell development and upsets the normal balance between bone formation and resorption. Therefore it is the critical period in the development of bone. Facial sutures close with difficulty leading to openbite. If imbalance occurs during hyperplastic phase then it causes irreversible damage to the tissues. If it occurs during hypertrophic phase then the growth may stop temporarily but will catch up later when adequate amounts of missing nutrients become available. the absence of natural diastema between the front deciduous teeth and shorter roots and interosseous rotation of the permanent teeth. Effect on bones: Kuftinec concluded bone develops in a manner similar to other soft tissues.

INFLUENCE OF FOOD CONSISTENCY ON OROFACIAL DEVELOPMENT Mouth is affected by a complex system of forces generated by muscular and respiratory functioning. cheeks. tongue. During palatal development a number of macromolecules increase during the critical ctages of palatal fusion like glycoproteins.
. a soft diet doesn’t provide adequate stimulus for the proper mastication. Klatsky and Fisher documented a direct relation between reduction in chewing power and demand made on supporting structures leading to underdeveloped muscles of mastication and incidence of malocclusion. the baby develops the earliest important functional influences on both the thrust and physiologic growth of the mandible. As a result of the sucking and pressing actions. In edentulous infants the centric occlusion and the control of lateral and protrusive movements are permitted and exercised by the interplay of the coronoid apophysis and the zygomatic arches. A variety of nutrient deprivation or excess as well as terratogenic agents can produce a very high incidence of this congenital anomaly as palatal tissues are very succeptible to environmental changes. the new born learns that food results from the action of sucking. which usually contain an abundance of raw vegetables offer adequate muscular stimulation and hence orthodontic problems. These muscles are later used in speech and as a result we see comparatively fewer speech problems in such children. infant and childhood diet. In animals . resulting in narrower maxillary arches. pharynx and palate. Studies suggest that an excess of vitamin A during this phase may lead to cleft palate formation. Much of this force generates as a result of masticatory activities that are dependant on the physical consistency of the food that is eaten. Breast nursing also aids greatly in developing the muscles of the lips. They stated that occasional or no consumption of coarse and fibrous food had a positive influence on the incidence of class II div 1 and skeletal type of malocclusions. Waugh. Similar observations have been made in humans leading to ‘ arch collapse syndrome’. Soon after birth.Worlds most common birth defect is the cleft lip and cleft palate (1 in 900 births). that are associated with breast feeding. If these are not supplied in the required amounts due to nutritional deficiency then will lead to the anomaly. It thus appears that these changes to softer food caused unfavorable changes in muscle tone and a tendency for skeletal and dental problems to develop. It was futher shown that these processes could be influenced by maternal. enzymes. actin and mucopolysaccharides. Singh and Chawla (1994) conducted a study on the contribution of diet in malocclusion in north Indian population. The diets of rural populations. followed by a feeling of well being. Effect of Nutrition on Teeth : Nutrition is most important during the period of time when teeth are undergoing matrix formation and calcification.

is influenced by the deficiency of vitamin A. For example. Effects of carbohydrates . Consequently severe Vitamin c deficiency has had the secondary effect of producing enamel hypoplasia. Now provided that enamel matrix formation has proceeded normally . Studies have also shown that Magnesium deficiencies lead to the development of Bruxism habit in individuals. The formative period of teeth can be divided into 3 segments. The enamel matrix being an epithelial tissue . proteins and fats on Dental Caries: Carbohydrates: They have been demonstrated to be important etiologic agents in dental caries. Vitamin A. Food stuffs rich in calcium. matrix formation. With adequate quantities of vitamin D the texture of forming enamel surface approaches perfection. The enamel that forms subsequently is hypoplastic and theoretically at least favours the accumulation of carbohydrates and microorganisms. deficiency of this vitamin results in atrophy of ameloblasts. Since the formation of primary and permanent teeth begins in uterine life and continues until the twelfth year( except the thid molars). it is the responsibility of the dentist to advice regarding dental health in young children and pregnant mothers. the other is the systemic nutritional factor . This drop in pH is indicative of acid production and most investigators conclude that bacterially produced acids are a major factor in the production of incipient carious lesions. Carbohydrates associated with formation of dental caries must:   Be present in the diet in meaningful quantities Be cleared slowly or ingested frequently
. a variety of situations may intervene to alter the enamel matrix calcification. which is important during the period of tooth development. about an hour. Another vitamin essential for enamel calcification is vitamin D. Immediately following the bathing of the teeth with carbohydrates there is a drop in pH of the plaque. the return of the tooth plaque to its original base line pH is rather slow. but in deficiency hypoplastic changes are observed. Nutritional disturbances during matrix formation may manifest themselves in imperfect enamel formation. phosphorus. DIET: Diet affects teeth in 2 distinct ways. One is the local effect and depends on the intra oral chemical or physical action on the external surfaces of the teeth of the .Under such circumstances the physical and chemical properties of the enamel could be altered in the direction of increased dental caries succeptibility. It is also well known that vitamin C is essential for the dentin and that initial dentin amrix formation must take place before enamel matrix formation can proceed.C and D should be recommended. enamel hypoplasia can be produced by dietary deficiency of calcium and phosphorus. matrix calcification and pre eruptive maturation.

springs and other attachments interfere with the patients ability to keep some portion of the teeth and brackets clean. presence of wires. Brackets and some of the resins used to bond them. it does point out to the possibility that under certain conditions modifications of the constituents dietary proteins may affect caries initiation. Fats: Dietary fats have a limited influence on dental caries. These problems can be associated with bonds or bands when combined with an improper diet involving unregulated sugar consumption and inadequate oral hygiene. Plaque accumulation has been shown to occur on brackets and some of the resins used to bond them. When dilute solution of fluoride is brought in contact with fully calcified enamel a union of fluoride and enamel results. Bracket configuration. caries and periodontal problems. Calcium from milk or protein from meat can neutralize or absorb acids. Many foods contain substances called buffers that neutralize any acids formed for eg. Protiens:
Be readily fermented by cariogenic bacteria
Although it is well known that carnivorous animals rarely develop tooth decay and that persons ingesting high protein diet have no particular succeptibility to dental caries. especially gingival to bands or brackets. However. commonly gingival to the bracket base. It is too early to assess the importance of this finding in terms of dental caries etiology. mechanism being the conversion of hydroxylappatite crystals of enamel to fluorapatite. It is recognized that fluoride incorporated into the tooth at the time of calcification show a definite resistance to tooth decay. ACTION OF FLOURIDE IN LIMITING TOOTH DECAY Fluoride in the concentration of 1ppm in drinking water is known to inhibit dental caries. elastics. The relationship between dental caries and the ingestion of fermentable carbohydrates has known for a long time. Feathrstone and Glatz in 1985 showed that measurable demineralization occurred in 4 weeks time. Experiments with animal suggest that the inhibition mechanism is a local one. Demineralisation: A common concern in orthodontics is the potential development of decalcification. When teeth are subjected to topical fluoride . Clinical observation indicate that one of the most common sites for demineralization appear to lie at the junction between the bonding resin and the enamel. Thus altering the surface properties of the enamel and possible interference with the metabolism of oral microorganisms. primarily by altering the physical and chemical properties of the tooth. fluorine displaces the hydroxyl ions
. very possibly associated with an oil film on the tooth surface.

using the same appliance and the resorbed areas are greater in extent and are repaired more slowly in animals with deficient diets. these changes include alterations of the lips. in its severest form it can lead to joint stiffening virtually immobilizing the patient. But care should be taken against excess fluoride consumed in the diet as it can cause cause systemic manifestations like osteoflurosis and if consumed during the tooth development . oral mucosa. 2. There are nutritional deficiencies that produce changes in the oral cavity. 2. Signs and Symptoms 1. This was supported by the study of Beck in 1931 on dogs. Marshall as early as 1930 concluded that animals on deficient diets showed greater degree of resorption than do those on adequate diets.
.as a reaction to periodontal tissue. or internal.from the hydroxyapatite crystal and forms fluorapatite which has reduced acid solubility. There are no nutritional deficiencies that by themselves cause gingivitis or periodontal pocket. tendons and muscle insertions resulting in vague pains of hands and feet. Their observations gave the information that the increase in the occurrence and severity of root resorption in moderate hypocalcaemia was related to an increase in alveolar bone turnover. Also topical fluoride application decreases the permeability of the enamel. 3. Glodie and King in 1984 conducted a study to investigate the tooth movement cycle and the area of root surface resorption in rats stressed with lactaion and diets deficient in calcium. Their results showed greater magnitude of tooth movementand overall root resoption was less in the animals which were stressed with diet . ROOT RESORPTION Root resorption is a common iatrogenic problem associated with orthodontic treatment. increased calcification of ligaments.as a reaction to pulp. this manifestation was attributed to increased bone metabolism and decreased bone density. bone as well as the periodontal tissues. Enstrom et al in 1988 investigated the effect of orthodontic force on periodontal tissues in normal and hypocalcaemic rats. increased density of various bones particularly pelvis and vertebrae. Many investigators have evaluated the effects of dietary factors on root resorption. NUTRITIONAL INFLUENCE ON PERIODONTIUM Majority of the research findings on the effects of nutrition on oral and periodontal tissues point to the following: 1. the animals with calcium and vitamin deficient diets were more succeptible to root resorption. it can lead to dental fluorosis characterized by brownish and corroded appearance of teeth. Resorption can be external.

nutritional deficiencies that can aggravate the injurious effects of the local irritants on the periodontium. oral microbial composition. protein synthesis growth and I. angular chelitis and inflammation of the oral mucosa.Q. but it produces a type of oral muscular activity or physiotherapy that can have a beneficial stimulatory effect on strengthening the periodontal ligament and increasing the density of the alveolar bone. Animal experiments suggest that vit A deficiency may predispose to periodontal disease. enlargement and bleeding Mc Canlies et al studied the effect of Vit C on the mobility of pig incisors under orthodontic forces and observed increased osteoclastic activity and large resorption lacunae in pigs with decreased or no Vit C in diet. But when a person is undergoing orthodontic treatment. Physical character of diet: Soft diet leads to plaque and calculus formation whereas hard and fibrous food provide surface cleansing action and stimulation which leads to decreased plaque and gingivitis. 2. 1. for the maintenance of Ca and PO4 balance and for the formation of teeth and bones. It has been suggested that a role in periodontal disease by one of the following mechanisms: ascorbic acid may play
a) Low levels of ascorbic acid influence the metabolism of collagen within the periodontium. Chewing of fibrous food s doesn’t increase gingival keratinisaton as believed. his or her
. wound healing. Effect of vitamin deficiency on periodontium. Diet can affect the periodontal health. glossitis and glossodynia.Folic acid deficient animals present necrosis of the gingival. 4. shape and texture. Vitamin C – its deficiency leads to Scurvy.It is essential for the absorption of calcium. b) Vit C deficiency interferes with bone formation and remodeling of the periodontal bone c) Its deficiency may aggravate the gingival response to plaque and worsen the edema. Its deficiency is characterized by the osteoporosis of alveolar bone and cemental resorption. The absence of inflammation ia the result of deficiency induced granulocytopenia. Vitamin B – deficiency leads to gingivitis. increased susceptibility to infection and disturbances in bone growth. periodontal ligament and alveolar bone without inflammation. Vitamin A – deficiency leads to keratinizing metaplasia of the epithelium. thereby affecting the ability of the tissue to regenerate and repair itself.There are however. Effect Of Orthodontic treatment On nutrient Intake As studied earlier. 3. Vitamin D .

This raises the nutritional requirement of the patient. Glucose is the energy source foe vital organs like brain. Vitamin C deficiency also affects the stability of orthodontic correction (ie). We must ensure adequate nutritional support in such patients. Vitamin A helps in epithelialization. Carbohydrates. Strause and Saltzmann also concluded that there was a decrease in the Mn and Cu intakes during orthodontic treatment. Protein is also important for imparting strength to the fracture repair. The physical and physiological and emotional stresses caused by orthodontic treatment sets in motion hormonal reactions that increase nutrient mobilization and utilization. which may lead to decreased bone remodeling. Fatty acids produce produce more energy and certain essential fatty acids must be supplied by the diet. uneven periosteal surfaces with osteoclastic activity. lack of Vitamin C interferes with collagen synthesis thus affecting both periodontal ligament and the formation of osteoid. which may influenced by ascorbic acid. NUTRITIONAL CONSIDERATIONS IN SURGICAL PATIENTS: The mouth is the portal for entry of food into the body thus maxillofacial surgery of these structures may result in impaired food intake both prior to and after surgery. collagen synthesis & cross linking and fibroblast differentiation. However hyperglycemia is not desirable. Protein is not an energy source but its primary purpose is for cellular proliferation and protein synthesis. Animal studies have shown that vitamin C deficiency causes enlarged endosteal spaces with osteoclasts. The diet of adolescent patients becomes more important because moving teeth creates an increased nutrient demand. 17-72% of orthodontic patients are deficient in Vitamin C. If it is absent then the wound healing is delayed. NUTRITIONAL CONSIDERATION IN ORTHODONTIC TOOTH MOVEMENT Tooth movement involves biologic responses to orthodontic forces. where the vitamin C deficient group experienced more relapse. Vitamin D and Calcium help in the healing of the hard tissues. Giordan (1997) studied the effect of orthodontic treatment on nutritional intake of the patient and concluded that there was a significant decrease in the fiber content of diet and higher fat and low carbohydrate soft food consumption. it affects retention. Vitamin C deficiency leads to impaired wound healing and collagen synthesis.dietary requirements and habits change which sjould be kept in mind before commencing the treatment. proteins and fatty acids are sources of energy. Patients require both an energy source and a protein source. promote growth and development and allowing the healing of periodontal tissues during treatment. This has been confirmed from experiments on guinea pig incisors. Vitamin E acts as an antioxidant and thus reduces the damage
.maintenance of diet is especially important to mprevent infection.

Zinc and protein deficiency impairs taste bud regeneration. These two control systems are interrelated. depending upon their chemical nature( Tabte6. The endocrine system constitutes endocrine glands which are situated in different parts of the body. thus impairing the taste sensation of the patient which in turn affects the dietary intake of the patient. chemical mediators or first messengers or hormones The endocrine glands are also called ductless glands because the hormones secreted by them are directly released into blood. Nutritional intake is dependant on several variables and one of them is Taste. ii. Steroid hormones are the corticosteroids and sex hormones. nervous system and endocrine system. Protein hormones and iii. Steroid hormones.from the free oxygen radicals. Vitamin K helps in activation of various clotting factors and thus is essential for blood clot formation during healing. Derivatives of the amino acid. 5-1).
CHEMISTRY OF HORMONES Hormones are classified into three types. Most of the functions of nervous system are executed by hormonal substances. Proteins hormones are the hormones secreted by pituitary gland parathyroid glands.
Endocrinology The activities of various organs in our body are controlled by two systems namely. STEROID HORMONES Steroid hormones are the hormones derived from cholesterol or its derivatives. PROTEIN HORMONES The protein hormones are large or small peptides. And. The hormones are transported by blood to the target organs or tissues in differenct parts of the body. most of the endocrine functions are controlled by nervous system. DERIVATIVES OF THE AMINO ACID TYROSINE
. where the actions are executed. pancreas and placenta. The functions of these glands are mediated by chemical substances which are called chemical messengers. called tyrosine. Large doses of Vitamin E also inhibit healing. i.

HORMONE RECEPTORS The receptors of the hormones are large proteins present in the target cells of the hormones. 2. Nucleus: Receptor of thyroid hormones is situated in the nucleus of the cell. HORMONAL ACTION INTRODUCTION Any hormone that causes changes in the target cells does not act directly on the cellular structure. each receptor can combine with only one hormone. Each cell has thousands of receptors.e. First the hormone combines with receptors present in the target cells to form a receptor-hormone complex.There are two types of hormones. Thyroid hormones and adrenal medullary hormones are derived from tyrosine. Cell membrane: Receptors of catecholamines(adrenaline and noradrenaline) and those of protein hormones(hormones of pituitary gland. cytoplasm or nucleus of the cells as follows: 1. which are the derivatives of the amino acid called tyrosine. parathyroid gland and pancreas) are situated in the cell membrane. The important characteristic feature of the receptors is that. any hormone can act on a target cell. 3. Cytoplasm: Receptor of steroid hormones is situated in cytoplasm of target cells. This receptor hormone complex induces various changes or reactions in the cells.
. Thus. each receptor is highly specific for one single hormone i. Situation of the Hormone Receptors The receptors are situated in cell membrane. only if the target cell has the receptor for that particular hormone.

Antidiuretic hormone
. 2. 4. Others affect only specific tissues called target tissues because only these tissues have the specific target cell receptors that will bind the hormones to initiate their actions. which have specific local effects on the adjoining tissues. 6. These hormones are transported in the blood to all parts of the body and cause many different reactions. 3. Examples of local hormones are acetylcholine released at the parasympathetic and skeletal nerve endings Most of the general hormones are secreted by specific endocrine glands. Examples are growth hormone. adrenocorticotropin from the anterior pituitary specifically stimulates the adrenal cortex. 5. Growth Hormone Adrenocorticotropin Thyroid-stimulating hormone Follicle-stimulating hormone Leutenizing hormone Prolactin
Posterior Pituitary Hormones: 1. which causes growth in almost all cells of the body. A few of the general hormones affect all or almost all cells of the body.
Overview of the Important Endocrine Glands and their Hormones:
Anterior Pituitary Hormones: 1.Hormones:
Definition: A hormone is a chemical substance that is secreted into the internal body fluids by one cell or a group of cells and has a physiological control effect on other cells of the body
Hormones may be local hormones or general hormones: Local hormones are the ones. For instance. causing it to release adrenocortical hormones.

when a person is exposed to pain. a bony cavity at the base of the brain.
Growth Hormone: Growth hormone. which are secreted within the hypothalamus and then conducted to the pituitary through the hypothalamic-hypophyseal portal vessels. It is connected to the hypothalamus by the pituitary stalk. control secretion of the anterior pituitary. a portion of the pain signal is transmitted to the hypothalamus. also called somatotrophic hormone or somatotropin does not function through a target gland. The pituitary gland secretes six important hormones that have just been reviewed. is a small gland that lies in the sella turcica. All the major anterior pituitary hormones besides Growth Hormone exert their principal effects by stimulating target glands. receives these signals from all possible sources in the nervous system. The hypothalamus.
Secretion from the posterior pituitary is controlled by nerve signals that originate in the hypothalamus and terminate in the posterior pituitary. In contrast. also called the hypophysis or master endocrine gland.
. in turn.
Control of Pituitary Secretions by the Hypothalamus: Almost all secretions from the pituitary gland are controlled by hormonal or nervous signals originating from the hypothalamus. For example. hormones called hypothalamic releasing and inhibitory hormones. It causes growth of almost all tissues of the body that are capable of growing by causing both increase in the size and number of cells and specific differentiation of certain types of cells such as bone cells and muscle cells. The pituitary gland is divisible into two parts: adenohypophysis or anterior pituitary and neurohypophysis or posterior pituitary. The functions of each of these hormones are discussed with the respective target glands.The pituitary gland.

In intramembranous bone growth. the jawbones can be stimulated to grow even after adolescence. once the epiphyses have united with the shafts. It us also seen that when blood level of STH (or testosterone) increases. growth hormone strongly stimulates the osteoblasts. its most obvious effect is to increase growth of the skeletal frame. supplementary lengthening of the mandible is greater than the maxilla. However. Age: The level of growth hormone reaches a peak during adolescence after which it decreases slowly with aging. increased use of the fatty acids for energy 3) decreased rate of glucose utilization throughout the body Regulation of Secretion: The secretion of growth hormone varies depending on a number of factors: 1. increased free fatty acids in the blood. but rather induces the formation of a secondary growth-promoting factor. These bones can continue to enlarge throughout life under the influence of growth hormone. Metabolic Effects of Growth Hormone: Apart from causing growth. this term has now been replaced by the more generic name “somatomedin”. growth hormone has no further ability to lengthen the bones. Although originally designated “sulfation factor” (because it stimulates the incorporation of radioactive sulfate into glycosaminoglycans of cartilage).Although growth hormone causes increased growth in almost tissues of the body. new bony trabeculae are formed in a more vertical orientation causing a closing of the Stutzmann Angle.
In animal experiments. It characteristically increases during the first two hours of deep sleep The Somatomedins: Although growth hormone is generally regarded as the principal hormone regulating skeletal growth. 2. GH has many metabolic effects as well. evidence has accumulated that growth hormone does not itself stimulate linear growth. Rate: The rate of growth hormone secretion varies in relation to the person’s state of nutrition or stress such as during (i) starvation especially during severe protein deficiency (ii) hypoglycemia or low concentration of fatty acids in the blood (iii) strenuous exercise (iv) excitement (v) trauma. finally falling to about 25 percent of the adolescent level in very old age. For instance. including 1) increased rate of protein synthesis in all cells of the body 2) increased mobilization of fatty acids from adipose tissue. it is seen that when experimental animals are treated with growth hormone. causing forward protrusion of the lower jaw. The prefix
. This results from: 1) increased deposition of protein by the chondrocytic and osteogenic cells 2) increased rate of reproduction of these cells 3) the specific effect of converting chondrocytes into osteogenic cells Growth hormone causes an increase in the length of the long bones where the epiphyses at the ends of the bones are separated from the shafts.

Following administration of growth hormone labeled with iodine 125. According to this hypothesis. B. these effects are weak and require unphysiologically high doses. Their most provocative observation. it might be reasonable to suspect that it arises from degradation of growth hormone itself. All known growth hormone actions on cartilage are attributable to
. Since growth hormone was itself inactive in this assay. C. Liver. it became apparent that the “sulfation factor activity” of plasma. however. Discovery of Somatomedins: The discovery of somatomedins is attributed to the pioneering work of Salmon and Daughaday. whereas very high concentrations are found in the liver.“somato” connotes the hormonal relationship to somatotropin. appears to be one site of production. and that this accumulation is reduced following hypophysectomy and restored by the administration of growth hormone. Salmon and Daughaday incubated small costal cartilage segments obtained from hypophysectomized rats with 35SO 4 in a nutrient medium containing the test sera. kidney and adrenal cortex. was that when serum from hypopituitary children was enriched by direct addition of growth hormone in vitro. When growth hormone was administered to a hypopituitary dwarf. although induced in vivo by growth hormone administration. At least four somatomedins have been identified denoted by the suffixes A. Another possibility is that proinsulin might serve as a prohormone for somatomedin as well as for insulin itself. it had no stimulatory effect on sulfate uptake. Actions of Somatomedins: Studies were undertaken to determine which of the metabolic effects ascribed to growth hormone are due to growth hormone itself and which require mediation of somatomedin. whereas the suffix “medin” indicates that somatomedin is an intermediary in growth hormone action. however. growth hormone would serve as a prohormone in a matter analogous to the release of insulin from proinsulin. These researchers drew on the experience of earlier workers who had shown that radioactive sulfate (35SO 4) preferentially accumulated by cartilage in-vivo. his serum regained its ability to stimulate 35SO 4 uptake in vitro. They showed that normal serum stimulated 35SO 4 uptake by cartilage in vitro whereas serum from hypophysectomized rats or hypopituitary children failed to do so. almost none is concentrated in the skeleton. D. Evidence has been advanced that somatomedin is not only insulin-like in its biological actions but that highly specific cellular receptors in tissues are incapable of distinguishing between insulin and somatomedin. Although growth hormone itself stimulates protein synthesis in liver and muscle in vitro. Origin of Somatomedins: So far the mechanism by which growth hormone stimulates somatomedin production remains unclear. Since the somatomedin molecule appears to be about one third as large as growth hormone. was not growth hormone itself.

the deficiency is of growth hormone alone. including the bones. The panhypopituitary dwarf does not pass through puberty and never secretes a sufficient quantity of gonadotropic hormones to develop adult sexual functions. Physiological Functions of ADH: Extremely minute quantities of ADH when injected into a person can cause antidiuresis. The giant ordinarily has hyperglycemia and full-blown diabetes may also occur. but the soft tissues can continue to grow and the bones can grow in thickness.that is. the permeability of the collecting tubules and ducts greatly increases and allows most of the water to be reabsorbed. the person becomes a giant as tall as 8 feet. Abnormalities of Growth Hormone Secretion: 1. the forehead slants forward. the features of the body develop in proportion to one another. supraorbital ridges. VP has no effect on osteoprogenitor cells limiting the differentiation of osteoblasts and consequently having little effect on bone growth (Yashar and Bernard. lower jawbone and portions of the vertebrae because their growth does not cease at adolescence. Vasopressin): ADH is secreted by the posterior pituitary gland.the person cannot grow taller. In the presence of ADH. Antidiuretic Hormone (ADH. after the epiphyses of the long bones have fused with the shafts. the lower jaw protrudes forward. In some dwarfs. decreased excretion of water by the kidneys. which allows extreme loss of water into the urine.somatomedin rather than a direct effect of growth hormone. that is. EFFECTS ON BONE It has a stimulatory effect on proliferation of stromal cells. thereby conserving water in the body. In general. VP significantly increases the numbers of bone colonies. these individuals do mature sexually. but the rate of development is greatly decreased. the fingers become extremely thickened and the hands develop a size twice the normal. Dwarfism: Most cases of dwarfism result from generalized deficiency of anterior pituitary secretion during childhood. 2. Vasopressin( VP) is an octapeptide hormone formed in neuronal cells of the hypothalamus and stored in the posterior lobe of the pituitary. Consequently. This condition is known as acromegaly. 3. All body tissues grow rapidly. Enlargement is especially marked in the bones of the hands and feet and in the membranous bones including the cranium. In vitro. 1996). If the condition occurs before adolescence. As a result. it remains to be determined which are due to a direct action of growth hormone and which require induction of somatomedins. For most of the extra-skeletal effects of growth hormone. large quantities of growth hormone are produced.
. Gigantism: Gigantism results from acidophilic tumors of the anterior pituitary during adolescence. bosses on the forehead. indicating proliferation of osteogenic stem cells. nose. the nose increases to as much as twice its normal size. Acromegaly: If an acidophilic tumor occurs after adolescence. the collecting tubules and ducts are almost impermeable to water. In the absence of ADH.

the effect of thyroid hormone on growth is manifest mainly in growing children. In hyperthyroid children. Therefore. 3) Effects on specific bodily mechanisms:
i. In hypothyroid children. The specific effect of thyroid hormone on growth pertains to its requirement to promote growth and development of the brain at an early age. On Carbohydrate Metabolism: Thyroid hormone stimulates all aspects of carbohydrate metabolism including rapid uptake of glucose by the cells. the rate of skeletal growth is greatly accelerated causing the child to become considerably taller at an earlier age. On Fat Metabolism: Increased thyroid hormone depletes the fat stores of the body. in all cells of the body the number of enzymes. However. It secretes two important hormones: thyroxine and triidothyronine that have a profound effect of increasing the metabolic rate of the body.
. Vasoconstrictor Effects of ADH: Higher concentrations of ADH have a potent effect of constricting arterioles everywhere in the body and therefore increasing the arterial blood pressure. Functions of Thyroid Hormones: 1) Increased transcription of genes: Thyroid hormones cause nuclear transcription of large numbers of genes. almost all of the thyroxine is eventually converted into thriidothyronine. One of the stimuli for causing intense ADH secretion is decreased blood volume. This occurs especially strongly when the blood volume decreases 15 to 25 percent. ii. Most of the hormone secreted by the thyroid gland is thyroxine. ADH is also called vasopressin. 2) Effect on growth: Thyroid hormone has both general and specific effects on growth. the bones also mature more rapidly and the epiphyses close at an early age so that the eventual height of the child may actually be shortened. In human beings. gluconeogenesis and even increased insulin secretion with all its secondary effects. decreases the quantity of cholesterol and increases the free fatty acids in the plasma by causing mobilization of lipids from the fat tissue. The net result is increase in the functional activity of all the cells of the body. Increased concentration of the extracellular fluid stimulates ADH production and vice versa. However. For this reason. enhanced glycolysis.
The Thyroid Hormones: The thyroid gland is located immediately below the larynx on either side and anterior to the trachea. the rate of growth is greatly retarded. the more potent form. structural proteins and transport proteins increases.Regulation of ADH Production: Osmotic concentration of the extracellular fluid regulates ADH production. It also greatly accelerates the oxidation of free fatty acids by the cells.

Osteoprogenitor cells proliferate and differentiate into osteoblasts by the stimulation of thyroid hormone receptors on their plasma membranes (Krieger et al. the condition becomes severe enough that the eyeball protrusion stretches the optic nerve enough to damage vision. On Basal Metabolic Rate: Because thyroid hormone increases metabolism in all cells of the body. On Cardiovascular System: Increased BMR increases blood flow. Thyrotoxicosis): The symptoms of hyperthyroidism include a high state of excitability. Hypothyroidism: Hypothyroidism results in myxedema in adults and cretinism in children. excess quantities of this hormone can increase the BMR 60 to 100% above normal. While there are contradictory effects.
Regulation of Thyroid Secretion: The secretion of thyroid hormones is under feedback control from the hypothalamus and the anterior pituitary and is affected by the circulating levels of T3 and T4 in the plasma. it sends a negative feedback signal to the hypothalamus and the anterior pituitary gland.
. When the level of T3 and T4 falls in the plasma. the vector of bone resorption and bone apposition is in the direction of bone apposition. v. Thyroid hormone therapy and hyperthyroidism often leads to bone resorption (Mosekilde and Melsen. extreme fatigue but inability to sleep. More often the eyes are damaged because the eyelids do not close completely over the protruding eyeballs.25(OH)2D3 and PTH (Cross et al. which increases the cardiac output and heart rate. 1978). sometimes acting in concert with 1. iv. 1988).. Exophthalmos: Most people with hyperthyroidism develop some degree of exophthalmos or protrusion of the eyeballs. nervousness and other psychic disorders. 2.l 9g7).iii. 1989). On Skeletal System: These hormones produced by thyroid clear cells (parafollicular cells) in a general way increase cellular metabolism and in particular increase bone growth and development (E rnsta ndF roesch. This restores the normal plasma levels of these hormones following which the feedback signal ceases. The cause of exophthalmos is edematous swelling of the retro-orbital tissues and degenerative changes in the extraocular muscles. mild to extreme weight loss. muscle weakness. In some patients.
Disorders of Thyroid Secretion: 1. As a result. increased sweating. Hyperthyroidism (Grave’s Disease. resulting in ulceration of the cornea.. intolerance to heat. the eyes become dry and irritated and often infected. This causes increased secretion of thyrotropin releasing hormone from the hypothalamus and thyroid stimulating hormone from the anterior pituitary both of which eventually result in increased secretion of T3 and T4 from the thyroid gland.

Each gland is composed of two distinct parts. The person develops diminished cardiac output. The adrenal medulla secretes the hormones epinephrine and norepinephrine in response to sympathetic stimulation. which proceeds to a shock-like state followed by death.Myxedema: Myxedema develops in adults with almost total lack of thyroid function. In the probable order of their importance. Increased potassium ion concentration in the extracellular fluid greatly increases aldosterone secretion 2. Increased activity of the rennin-angiotensin system also greatly increases aldosterone secretion
3. muscular sluggishness. Apart from the features of hypothyroidism seen in the adult.Aldosterone Total loss of adrenocortical secretion causes death of a person unless the person receives extensive salt therapy. The adrenal cortex secretes hormones called corticosteroids. Cretinism: Cretinism is caused by extreme hypothyroidism in fetal life. These hormones are of two major types. this condition is characterized especially by failure of growth and mental retardation. The Adrenocortical Hormones: The two adrenal glands lie at the superior poles of the two kidneys. There is swelling of the face with bagginess under the eyes. Aldosterone causes reabsorption of sodium and loss of potassium in the collecting tubules. Without mineralocorticocoids. they are as follows: 1. These patients show fatigue and extreme somnolence with sleeping up to 12 to 14 hours a day. The mineralocorticoids are so called because they affect the electrolytes of the extracellular fluidssodium and potassium in particular. the sodium and chloride concentrations decrease. the potassium ion concentration of the extracellular fluid rises. decreased cardiac output and weight gain.
. The glucocorticoids have gained their name because they have an important effect in increasing the blood glucose concentration.mineralocorticoids and glucocorticoids. infancy and childhood. Aldosterone is the principal mineralocorticoid and cortisol is the principal glucocorticoid.the outer adrenal cortex and the inner adrenal medulla. Functions of Mineralocorticoids. Regulation of Aldosterone Secretion: Four factors are known to play essential roles in aldosterone secretion. Increased sodium ion concentration in the extracellular fluid very slightly decreases aldosterone secretion 4. the total extracellular fluid volume and blood volume become greatly reduced. small amounts of sex hormones called androgenic hormones are also secreted by the adrenal cortex. ACTH from the anterior pituitary is necessary for aldosterone secretion but has little effect in controlling the rate of secretion. In addition.

This condition is called adrenal diabetes.l 9g4. The different types of stress that increase cortisol release are trauma of almost any type. l9g0). 2. While osteoclasts are normally increased in bone and bone marrow cultures with PGE2 it also can sometimes initially inhibit the activity of osteoclasts in tissue culture (yonaga et al-.. causes increased adrenocortical secretion of cortisol.PGs stimulate osteoprogenitor cells to proliferate and differentiate so that osteogenesi is increased(c hyun and Raisz. Jeee t al.Functions of Glucocorticoids: Cortisol
1. 1919. ueda et al.. On Fat Metabolism: Cortisol promotes mobilization of fatty acids from adipose tissue.Several cytokines and hormones induce PGE secretion in bone which in turn effects cytokine activity. At the same time.. Decreased Glucose Utilization by the Cells: Cortisol causes a moderate decrease in glucose utilization by cells everywhere in the body . fats etc. by the liver ii. pGE. 5. as a product of arachadonic acid from cell membrane phospholipids. first of all. 1986). surgery etc. Stimulation of Gluconeogenesis: By far the best-known metabolic effect of cortisol is gluconeogenesis. FUNCTION OF GLUCOCORTICOIDS ON SKELETAL SYSTEM: Glucocorticoids affect bone mass by. cortisol also increases the liver and plasma proteins 3. 4. intense heat or cold.Oppositely. This is caused by both decreased protein synthesis and increased catabolism of protein already in the cells. stimulating osteoclast activation( Schelling et al. l9g5. decreasing intestinal Ca++ absorption. physical or neurogenic.Both the increased rate of gluconeogenesis and the reduction in the rate of glucose utilization causes the blood glucose concentrations to rise.
On Carbohydrate Metabolism:
i.. Ibbotson et al. which also increases their utilization for energy. Glucocorticoids inhibit arachadonic acid formation and therefore PG. pG can stimulate bone formation. is the predominant prostaglandin in bone. synthesis of carbohydrates from non-carbohydrate sources such as proteins. 1984). This causes a decrease in plasma Ca++ which through
. Cortisol also depresses the formation of RNA and subsequent protein synthesis. This increases the concentraton of free fatty acids in the plasma. PROSTAGLANDINS Most cells in the body and osteoblasts in bone secrete prostaglandins( PG). On Protein Metabolism: Cortisol causes reduction of the protein stores in essentially all body cells except those of the liver. In Stress and Inflammation: Almost any type of stress. that is. infection.' 1980) and loss of osteoblastic junctional complexes( Shene t al.

On the other hand. Increased calcium and phosphate absorption from the bone 2. as in rickets. However. Oversecretion could lead to secondary hyperparathyroidism (Gennari. Glucocorticoids block the synthesis of various osteogenic proteins which.1 979) sometimes through action on osteoblast receptors which inhibit osteogenesis . Vitamin D itself is not the active substance that actually causes these effects. reduces bone formation as well (peck et al.when activated. Instead the Vitamin D must first be converted through a succession of reactions in the liver and the kidneys to the final active product.. The predominant effect of glucocorticoids is to inhibit IGF-I synthesis in osteoblasts which inhibits mitosis. l9g4). 1. any condition that increases the calcium ion concentration above normal causes decreased activity and reduced size of the parathyroid glands. The rise in calcium is caused by: 1. Effect of Parathyroid Hormone on Intestinal Absorption of Calcium and Phosphate: Parathyroid hormone greatly enhances both calcium and phosphate absorption from the intestines by increasing the formation in the kidneys of calcitriol from Vitamin D.. which leads to a decrease of bone formation and therefore leads to a decrease in bone mass.. Such conditions include: (1) excess quantities of calcium in the diet (2) increased Vitamin D in the diet (3) bone absorption caused by other factors
. Parathyroid Hormone and Calcitonin: Vitamin D and its role in Calcium and Phosphate Absorption: Vitamin D has a potent role in increasing calcium absorption from the intestinal tract. which are located immediately behind the thyroid gland. Parathyroid hormone causes rapid increase in blood calcium and drop in phosphate levels. Parathyroid Hormone: Parathyroid hormone is secreted by the four parathyroid glands. tSdS. peJt et al.
Vitamin D. Extensive use of glucocorticoids invariably causes massive loss of trabecular bone (Bressote t al. the glands will hypertrophy. If the decreased calcium ion concentration persists. in effect. Glucocorticoid receptors on osteoblasts .negative feedback stimulates the parathyroid gland to secrete PTH.25-dihydroxycholecalciferol also called calcitriol.. 1967). inhibit Type I procollagen formation and activated receptors on osteoprogenitor cells inhibit mitosis. Control of Parathyroid Secretion: Even the slightest decrease in calcium ion concentration in the extracellular fluid causes the parathyroid glands to increase their rate of secretion within minutes. Decreased renal excretion of calcium Decline in phosphate concentration is caused by excessive renal phosphate excretion.

the nervous system is depressed and the reflex activities of the central nervous system can become sluggish...I n the long term PTH can cause differentiation of osteoprogenitor cells into osteoblasts (Skjodt et al. 1988. exposing bone surfaces and releasing osteoclast activating factors such as prostaglandins(H oltrop et al. PTH binds to cell membrane receptors in osteoprogenitor cells. 1989). 1989. Calcitonin:
. Multinucleated osteoclasts although without receptors to PTH. 1978).. In osteoclasts PTH stimulates cell adhesion molecules. The hormone is secreted when lowered levels of calcium circulate through the vascular system of the gland. releasing calcium from the calcified matrix into the vascular circulation. which results in tetany. and lysosomal enzyme production( Barone t al. 1989a). It is secreted by osteoblasts probably having paracrine functions like other cytokines( Hock et al. ruffled borders subadjacent acidity. 1986. is called “carpopedal spasm”.Burger et al. activated osteoclasts resorb bone. size.. Hyperparathyroidism: Hyperfunctioning of the parathyroid glands results in hypercalcemia.. Symptoms of hypercalcemia begin to appear when the blood level of calcium rises above 12 mg/dl and become marked above 15 mg/dl. Parathyroid hormone-related peptide (PTH-RP). 1988). Other features include constipation and lack of appetite. 1974.ROLE OF PARATHYROID ON SKELETAL SYSTEM AND BONE: A polypeptide. This feedback system also inhibits secretion when calcium levels rise. which usually develops before tetany develops in other parts of the body.. When the level of calcium in the body fluids rises above. increases motility.... Both stimulate bone resorption although PTH-RP does not stimulate the differentiation of osteoblasts from osteoprogenitor cells and is not involved with the coupling effect in bone... a long chain peptide. is produced by the principal cells of the parathyroid glands.The affect is to generally increase metabolism.B aron et al. 1988). to cause osteoblasts to become osteolytic.This activation takes several hours. Tetany ordinarily occurs when the calcium ion concentration falls from its normal level of 9-11 mg/dl to about 6 mg/dl. is produced by many tissues and malignancies associated with hypercalcemia such as hyperparathyroid adenomas( Goltzman et al.. allowing easy initiation of action potentials and causing them to discharge spontaneously to elicit tetanic muscle contractions. Physiologically.
Hypoparathyroidism and Hyperparathyroidism: Hypoparathyroidism: Hypoparathyroidism causes hypocalcemia. 1988).B roaduse t al. Tetany in the hands. Whem the extracellular fluid calcium ion concentration falls below normal.PTH can have contradictory effects on osteoblastic activity (Tam et al. 1986). 1992).. ultimately respond to PTH stimulation by activating dormant osteoclasts or by developing new osteoclasts from the fusion of mitotic monoblastic precursors( Rouleaue t al.M iller. 1989b). 1982):its immediate effect is to inhibit secretory activity (Hock et 'at. the nervous system becomes progressively more excitablebecause this causes this causes increased neuronal membrane permeability of to sodium.PTH-RP and PTH have common receptor sites in bone (Nissensone t al. PTH. osteoblasts and osteocytes( Rouleaue t al.

especially excess amounts of carbohydrates and proteins.. Then.. however. However. This allows the osteoclast to become motile. between meals.. when the muscle is stimulated by insulin. the membrane permeability greatly increases. this may follow calcitonin-mediated monocyte deactivation (Nong et al. 1972). The hormone is associated with energy abundance.. insulin secretion decreases rapidly and the liver glycogen is split back to glucose. It reacts with target cells by binding to cell membrane receptors.. 1984). there may be a rebound effect which increases the numbers of osteoclasts to. The first cellular messenger is cAMP. immediately reducing the numbers of osteoclasts on the bone surfaces (Chambers et al. Effects of Insulin: 1.
Insulin and Glucagon: Insulin is secreted by the β cells of the Islets of Langerhans.. 1982).1 989a. On Carbohydrate Metabolism:
i. The osteoclasts respond by reducing the size and shape of their ruffled borders with attending inhibition of cell adhesion (Chambers et al. 1988.Calcitonin is secreted by the thyroid gland. insulin is secreted in great quantity. Muscle: The resting muscle membrane is only slightly permeable to glucose. Calcitonin has its major influence on osteoclast inhibition although there are some reports which emphasize its facilitory action on osteoblasts (F arleye t al. 1989). 1974). Liver: One of the most important effects of insulin is to cause most of the glucose absorbed after a meal to be immediately stored as glycogen. The resultant effect is significantly to reduce bone resorption for about 20-24 hours (Wener et al. Insulin also stimulates the synthesis of muscle glycogen. that is. 1989). This hormone also plays an important role in calcium metabolism. 1989).I n part. when the blood glucose level begins to fall. It decreases the absorptive activity of the osteoclasts It also decreases the formation of new osteoclasts
ROLE OF CALCITONIN IN SKELETAL SYSTEM This 32-amino acid peptide is primarily secreted by parafollicular cells in the thyroid gland and to a Iesser extent by neurons (Heersche et al. Calcitonin is secreted by calcitonin producing cells when vascular Ca++ levels are high (Deftos and Roos. 2. it binds to osteoclast receptors. When the
.. or above baseline( Klaushofere t al. It is antagonistic in its action to parathormone and decreases the blood calcium levels by the following two mechanisms: 1. Primarily. when there is great abundance of energy giving foods in the diet.After this time. ii.b ).

has several functions that are diametrically opposite to those of insulin. it was believed that insulin secretion is controlled almost entirely by blood glucose concentration. Control of Insulin Secretion: Formerly. Other Effects:
. 2. the administration of either growth hormone or insulin one at a time causes almost no growth. Thus. Brain: Secretion of insulin has little or no effect on uptake of glucose by the brain as even in the absence of insulin brain tissue can take up glucose. 4. It has been seen that in depancreatized and hypophysectomized rats. insulin promotes the conversion of all this excess glucose into fatty acids. secretin which are secreted after a meal cause an anticipatory increase in insulin secretion in preparation for the glucose and amino acids to be absorbed from the meal. Amino acids administered in the absence of a rise in blood glucose concentration cause only a small increase in insulin secretion. when administered at the time of raised blood glucose levels.
Glucagon: Glucagon. However. 3. Effects on Glucose Metabolism: The major effects of glucagon on glucose metabolism are: (1) breakdown of liver glycogen (glycogenolysis) (2) increased gluconeogenesis in the liver. all of which lead to fat storage in adipose tissue. Insulin also inhibits gluconeogenesis. Insulin also promotes fatty acid synthesis. On Fat Metabolism: Insulin is a “fat sparer. unlike other cells of the body. iii. amino acids strongly potentiate the glucose stimulus for insulin secretion. Both these effects greatly enhance the availability of glucose to other parts of the body. the glucose-induced secretion of insulin may be twice as much in the presence of excess amino acids. a hormone secreted by the α-cells of the Islets of Langerhans when the blood glucose concentration falls.” First insulin increases the utilization of glucose by most of the body’s tissues. However. it is now known that there are other factors that play an important role as well. which automatically decreases the utilization of fat. On Growth: Insulin has a synergistic effect on growth along with growth hormone since it is required for the synthesis of proteins. Gastrointestinal hormones like gastrin. On Protein Metabolism: Insulin promotes protein formation and prevents the degradation of proteins.quantity of glucose entering the liver cells is more than can be stored as glycogen. Yet a combination of these two hormones causes dramatic growth.

about 50 percent more than the females.1 978. in this instance. androgens have a stimulatory effect on osteoblasts (E inhorn et al. 1989). Regulation of Glucagon Secretion: Increased blood glucose concentration inhibits glucagon secretion.
.Like estrogens.. .Glucagon activates adipose cell lipase making increased quantities of fatty acids available to the energy systems of the body. Bjomsson et al. A beneficial effect of glucagon is that it prevents a fall in blood glucose. The blood glucose concentration is the most potent factor that controls glucagon secretion. This is the same effect that amino acids have on insulin secretion. Testosterone: Apart from its effects in causing growth of the secondary sexual characters. Because of the ability of testosterone to increase the size and strength of bones. tOSl. The effect of blood glucose concentration on glucagon secretion is exactly opposite to that of insulin secretion. Estrogens may have indirect effects on osteoclast activity by reducing its resorptive function (Arnett et al. 19gg. It is well known that loss of estrogen in post-menopausal women leads to bone loss and osteoporosis( Raisz et al.. Thus. Because of the great effect that testosterone has on the body musculature. and androgens all have osteo-stimulatory actions. Effect on Bone Growth and Calcium Retention: Testosterone increases the total quantity of bone matrix and causes calcium retention.Estrogen therapy therefore tends to decrease the onslaught of osteoporosis( Raisz. l9g3). l9g9).25(OH)2D3 and calcitonin (Cieema et al.. The increase in bone matrix is believed to result from the general protein anabolic functions of testosterone. Testosterone is also used in old age as a “youth hormone” to improve muscle strength and vigor. the blood concentration of glucagon increases fourfold to fivefold. the glucagon and insulin responses are not opposite. It also inhibits the storage of triglycerides in the liver. What causes this is not understood because the blood glucose concentration does not necessarily fall. which is a function of testosterone. it is often used in old aged men to treat osteoporosis. testosterone has some other functions as well: Effect on Bone Formation and Muscle Development: One of the most important male characteristics is the development of increasing musculature after puberty.. as occur in the blood after a protein meal. this also makes fatty acids available to other tissues of the body. Excitatory Effect of Exercise: In exhaustive exercise. it is widely used by athletes to improve their muscular performance.' 1989).' 1989). One mechanism of estrogen action is to increase the osteogenic activity of 1. SEX HORMONES Estrogens. which prevents the liver from removing fatty acids from the blood.But research to find estrogen receptors on osteoblasts has been ambiguous and the effects on various osteogenic substrates is variable( Chen and Feldman. progestins. Colstone t at. stimulate the secretion of glucagon.. Excitatory Effect of Amino Acids: High concentrations of amino acids.

Sandy and M. at puberty. The movement of incisors and molars was measured directly. on tooth movement was studied using New Zealand white rabbits. Abstract The effect of flurbiprofen. estrogens also cause early uniting of the epiphysis with the shafts of the long bones.
Prostaglandins and tooth movement J. estrogens serve other functions such as: Effect of Estrogens on the Skeleton: Estrogens cause increased osteoblastic activity. this can lead to osteoporosis. Control animals received the vehicle only. the ovaries secrete almost no estrogens. Experimental animals were administered daily flurbiprofen (10 mg/Kg) via a catheter passed orally into the stomach. Under general anaesthesia. Because this can greatly weaken the bones and lead to bone fracture. Harris Eur J Orthod (1984) 6 (3): 175-182. the female growth rate becomes rapid for several years.
Direct and radiographic measurements showed movement within the experimental and control groups. This effect is much stronger in the female than in the male. Therefore. and movement between the first and second molars measured from radiographs.
. As a result. However.
Osteoporosis of the Bones Caused by Estrogen Deficiency in Old Age: After menopause. the radiographic measurements showed a trend towards decreased tooth movement in the experimental animals. R. springs were ligated between the lower first molars and incisors resulting in approximation of these teeth. a large share of post-menopausal women are treated prophylactically with estrogen substitutes. and the remaining animals after 14 days. In severe cases. growth of the female usually ceases several years earlier than growth of the male. Osteoclast activity in the area of crestal bone adjacent and mesial to the first molar was examined histologically. A pair of animals (experimental and matched control) was sacrificed after 3 and 10 days.Estrogen: Apart from its effect in causing growth of the female secondary sexual characters. However. This estrogen deficiency leads to (1) diminished osteoblastic activity (2) decreased bone matrix (3) decreased deposition of bone calcium and phosphate. Experimental animals were matched to a control animal of the same sex and weight. but no significant difference between them. a prostaglandin cycloxygenase inhibitor.

S. However these findings suggest other undefined mechanisms remain unaffected. Pages 256-262 Original article The effect of altered bone metabolism on orthodontic tooth movement*1 Ronald J. The experimental diet was identical to that fed the controls except for a decrease in the calcium (0.D.
CALCIUM METABOLISM OR CALCIUM HOMEOSTASIS The Homeostatic Pathways for Calcium and Phosphorus Differ Quantitatively
. Fruge.dent. phosphorus 0. Jr. Dr.20 percent) ratio. D. suggests non-steroidal anti-inflammatory drugs can partially inhibit orthodontic tooth movement. and a bone ash analysis. the second and fourth premolars were moved toward each other with a reciprocal elastic force of 100 Gm.D. were randomly divided into two groups of six..42 percent). which included Paragon 1301 staining of undecalcified sections. USA Abstract The purpose of this study was to determine how bone remodeling changes induced by nutritional hyperparathyroidism affect tooth movement through alveolar bone. Robert Shaye D. and James F. Radioimmunoassays during the experiment showed that the test animals had significantly elevated levels of parathyroid hormone.S.
American Journal of Orthodontics Volume 80. The controls were fed a standard dog diet (calcium 0. approximately 1 year old.. September 1981. New Orleans. together with a significant decrease in the number of osteoclasts in the bone adjacent to the induced tooth movement in the experimental animals. Twelve weeks later the animals were killed and the mandibles were prepared for laboratory evaluation. At the tenth week of diet administration. indicating a probable state of hyperparathyroidism. Issue 3. Twelve beagle dogs. scanning electron microscopy. following extraction of the lower third premolars.D. These findings suggest that. Midgett Ph. as well as bone remodeling changes consistent with high PTH levels.This observation. Laboratory data indicated that the hyperparathyroid animals had significantly decreased bone density..54 percent. in addition to applied force. From the Louisiana State University School of Dentistry. The most likely mechanism is the inhibition of prostaglandin synthesis with a resultant inhibition of osteoclast activity and bone resorption. La. tooth movement is dependent upon the state of calcium metabolism in alveolar bone.med.12 percent) to phosphorus (1. The clinical data revealed more rapid tooth movement in the experimental animals.

Dietary intakes may vary widely. so the primary determinant of net calcium uptake from the GI tract is calcium absorption. This component of the calcium flux partly results from sloughing of mucosal cells that line the GI tract and also from calcium that accompanies various secretions into the GI tract. Only about one third of ingested calcium is actually absorbed from the GI tract. This component of calcium metabolism is relatively constant. the net uptake of calcium from the GI tract presents a daily load of calcium that will eventually require elimination. As much as 500 mg/day of calcium may flow in and out of the bones.000 mg/day of calcium. The ultimate fate of each substance is determined primarily by the gastrointestinal (GI) tract. and the bones. Kidneys.
. Calcium Handling by the GI Tract. Approximately 150 mg/day of calcium actually enter the GI tract from the body. but excessive calcium intake can result in soft tissue calcification or kidney stones. and therefore. Intestinal absorption is important in regulating calcium homeostasis. often it is reduced in older adults. The 150 mg/day of calcium excreted in the urine represent only about 1% of the calcium initially filtered by the kidneys. Bone mineral is constantly resorbed and deposited in the remodeling process. In overall calcium balance.Both calcium and phosphate are obtained from the diet. the kidneys play an important role in regulating calcium homeostasis. Bone in an average individual contains approximately 1. and Bones. but an “average” diet contains approximately 1.000 g of calcium. the kidneys. The efficiency of calcium uptake from the GI tract varies with the individual’s physiological status. The percentage uptake of calcium may be increased in young growing children and pregnant or nursing women. the remaining 99% is reabsorbed and returned to the blood. the remainder is excreted in the feces. The primary route of elimination is via the urine. Intakes up to twice that amount are usually well tolerated. Since bone calcium serves as a reservoir. small changes in the amount of calcium reabsorbed by the kidneys can have a dramatic impact on calcium homeostasis. both bone resorption and bone formation are important in regulating plasma calcium concentration. Therefore.